Hey,I'm trying to underclock my memory clock using MSI Atferburner, but it seems I can't underclock it.First I overclocked the core from 840 to 900 and thought I underclocked my memory to 600, However, everytime I monitor it, the core clock seem to change but the memory is still at 1250.Any ideas?I'm using win7 64bit.

There is nothing wrong with your card, it's just broken as designed...Barring an unofficial hardware hack or gpu bios reflash there is little you can do.

For some obscure reason, when introducing the 69xx family of cards AMD decided to link their minimum memory clock to the current core clock: min_memory_clk = core_clk - 125MHz.The 7xxx series is no longer affected by this weird limitation.